The demand for data communications services is currently increasing at a greater and greater rate. This increase in end-user demand for more and more bandwidth is largely the result of the Internet and other data-intensive, high bandwidth applications. The Internet, in recent years, has experienced explosive growth in both the number of end users and the volume of traffic being sent. Consumers and other end-users are demanding higher bandwidth connections and faster Internet access. Another source for the demand is the increasing use by businesses of data communications networks (including traffic over the Internet) for the transmission of documents and email for both intra-office and inter-office purposes.
The demand from businesses and consumers for broadband service is increasing as most are no longer satisfied with dial-up Internet access connections. Many businesses and consumers are now requesting multi-megabit access bandwidth in order to participate in the e-revolution and to integrate their telecommunication services.
As more and more end users generate more and more data traffic, the demand for faster and faster data links will rise sharply. Currently, telecommunication companies are scrambling to meet the current demand while attempting to estimate future demand. A major roadblock preventing telecommunications providers from offering broadband services universally, however, is the local loop, referred to by some as the ‘dirt roads of the information superhighway.’ In order to offer high bandwidth access, these dirt roads must be paved, and in order to do so, ILECs and CLECs must invest an enormous amount of time and money in massive optical fiber infrastructure upgrades.
Currently, some carriers are using fiber optic cable to provide the high bandwidth pipes needed to satisfy the current bandwidth demand. Optical fiber, however, is not replacing legacy the copper cable plant. It is used mainly in new cable installations and in some cases to connect central offices (COs) to remote nodes, commonly referred to as Fiber to the Curb (FTTC). Notwithstanding the installation of optical fiber cable, the ‘last mile’ from the curb, node or patch panel to the customer premises comprises unshielded twisted pair copper cable.
Today, deployment of fiber in the local loop in the United States, for example, is relatively low. As few as 3% of the approximately 750,000 office buildings, 9% of curb cabinets and 19% of outdoor cabinets are connected by fiber optic cable to the CO. Optical fiber cable deployment in Europe is even lower. Within 15 years, deployment of fiber in the loop in the United States is expected to reach only 50%. The cost of bringing fiber to the home, for the United States, has been estimated to be in the hundreds of billions of dollars. Thus, universal deployment to every building in the local loop is an extremely time consuming and costly effort, one not likely to be undertaken by the major carriers.
In response to customer demands for bandwidth, many companies are providing alternatives to the last mile of copper, such as LEO satellite broadband, optical fiber, CATV cable, Wireless Local Loop (WLL) and other technologies. Another available technology is xDSL modem technology. Many ILECs, CLECs, and ISPs, which typically are under huge competition, have embraced DSL technology as an immediate broadband solution to serve the current demand by getting more out of the copper plant without waiting for the lengthy installation of fiber. As with many new technologies, however, many carriers face difficulties with the deployment of DSL, such as distance limitations, the lack of service parameter guarantees and the lack of the kind of reliability afforded by fiber.
Digital Subscriber Loop (DSL) technology refers to several types of services that use advanced modem elements to transmit digital signals from a data source over copper wire. DSL modem elements permit high data rate transmission of data over the public switched telephone network (PSTN). DSL modem elements can transmit data at multiple megabit speeds using sophisticated known signal processing techniques that permit voice and data to travel simultaneously over the same analog copper twisted pair wire.
Typically, the DSL services require two modem elements, one of that is located in the CO of the Incumbent Local Exchange Carrier (ILEC). CLECs, however, may collocate their DSL access multiplexers in the CO of the RBOC, enabling them to run over unbundled copper pairs, offering broadband connections to businesses.